Press cages on screw presses

ABSTRACT

A screw press for extracting liquids from materials such as cotton seeds, copra, linen seeds, bagasse an the like, wherein the screw acts as a conveyor through a press cage having decreasing diametral dimensions and spacings for varying the pressure on the material.

United States Patent Braten May 16, 1.972

1541 PRESS CAGES ON SCREW PRESSES [72] inventor: Olaf Georg Braten, PO. Box 9, 5401 Stord, Norway 22 Filed: Sept. 1, 1970 21 Appl.No.: 68,649

[30] Foreign Application Priority Data Sept. 2, 1969 Norway ..3516/69 [52] US. Cl ..100/127, 100/145 [51] Int. Cl ..B30b 9/06 [58] Field ofSearch ..l00/126, 127,128, 129, 145, 100/146, 147, 148, 149, 150, 37

[56] References Cited UNITED STATES PATENTS French ..100/127 FOREIGN PATENTS OR APPLICATIONS 814,702 3/1937 France ..lO0/127 French et a1. 100/1 29 X French et a1. 100/127 X Primary Examiner-Peter Feldman Attorney-Waters, Roditi, Schwartz & Nissen [5 7] ABSTRACT A screw press for extracting liquids from materials such as cotton seeds, copra, linen seeds, bagasse an the like, wherein the screw acts as a conveyor through a press cage having decreasing diametral dimensions and spacings for varying the pressure on the material.

2 Claims, 4 Drawing Figures PATENTEDMHsmz 3.562.679

SHEET 2 [IF 2 FIG.4.

PRESS CAGES ON SCREW PRESSES The present invention relates to improvements in screw presses, more particularly improvements in the grid bodies or socaIIed press cages for screw presses of the type utilized for extracting liquid from materials such as cotton seeds, copra, linen seeds, bagasse from the sugar cane industry or the like. Screw presses for such purposes must be designed for internal pressures of several hundred kp/cm and in some designs the maximum pressure may exceed 1,000 kp/cm A material such as sugar canes, which are initially finely divided in hammer mills or the like, is firstly passed through a diffuser. The material has initially relatively small fiber content and large water content. By reducing the water content from 80-90 percent to 45-50 percent the pressed fibers, the so-called bagasse, may go directly to the boiler as fuel. The steam is utilized for generating power and energy for the evaporator plant.

The dewatering of the bagasse can take place mechanically utilizing mills or by means of presses. Of known press constructions can be mentioned socalled disk-presses, also called cone presses, and furthermore single screw presses which are provided with a vertically divided press cage which again is assembled from one or more sections. The separate sections are usually hinged about a pivot axis which is positioned above or below the press such that the separate sections can be turned aside for inspection etc. It can be referred to U.S. Pat. No. 3,1 1 1,080 which shows examples of such presses.

In screw presses the material which shall be pressed is conveyed through the press cage by the screw which thus is operating as a conveyor. The cross-sectional area of the press space between the screw and the surrounding cage is usually reduced from the inlet to the outlet end of the press or press cage. Thereby is compensated for the liquid which is drained out simultaneously as the pressure in the material is increased towards the outlet end. The reduction of the cross-sectional area is usually obtained either by designing the screw as a conical body having increasing diameter towards the outlet end or by designing the press cage with increasingly reduced diameter towards the outlet end. The present invention relates to screw presses of the latter kind.

The improvements in the press cage in a screw press in accordance with the invention is of the kind where the press cage comprises a plurality of plate or disc-shaped cage elements assembled into a number of horizontally and/or vertically divided sections assembled in pairs, and mounted in a cage frame, each section comprising a cast or welded unit, the press cage having a progressively reduced inside diameter from the inlet to the outlet end, and the invention is characterized therein that the sections in the press cage have constant or uniform inside diameter, said inside diameter of consecutive section pairs gradually decreasing from the inlet to the outlet end of the cage, the pairs of press cage sections mounted in said frame with a spacing therebetween, said spacings provided with separate compression rings each of which has a conical inside face matching the adjoining inside faces of adjacent press cage sections, each of said compression rings comprising complementary ring parts supported by the respective adjacent press cage sections.

Through this construction is obtained several advantages of which can be mentioned that one obtains a simplified making of the screw press and a simplified assembly of same, simultaneously as one can obtain a larger maximum working pressure in the press in spite of the fact that the total weight of the screw press can be reduced substantially in comparison with corresponding screw presses of conventional design.

The invention shall in the following be described'further with reference to the accompanying drawings which are showing an embodiment for a screw press in accordance with the invention and wherein:

FIG. 1 is showing a schematic side view, looking towards one end of a press cage on a screw press in accordance with the invention,

FIG. 2 is showing a plan view of one press cage section in accordance with the invention,

FIG. 3 is showing a plan view similar to FIG. 2 of a second embodiment of a press cage section in accordance with the invention,

FIG. 4 is showing a longitudinal cross-sectional view through a press cage on a screw press in accordance with the invention, and wherein the press cage assembly as shown comprises all together three separate sections.

As it appears from FIG. 1 the press cage is here divided horizontally and comprises an overbridge l and an underbridge 2. The bridges are designed in the shape of sections and these comprise plate-shaped bridge elements which on opposing sides of the press cage are provided with, or altematively welded to, tube blanks 3,3 for the positioning of bolts 5 for bolting the overbridge to the underbridge. The press cage is otherwise in per se known fashion provided with a tubular drain means 9 which is supported by side brackets 7 which preferably by means of bolts are fixed to the overbridge and the underbridge, respectively. A longitudinal beam 6 serves as stiffening member for the construction. The underbridge is as indicated anchored to a support frame 10.

The construction of the separatesections of the press cage appears more clearly from FIGS. 2 and 3. In the embodiment shown in FIG. 2 each cage section comprises a number of bridge elements in the shape of plate elements 12, 12 etc. which on opposite sides are welded to tube blanks 3 along bilateral welding seams 14,14 etc., and these welded-together bridge elements are permanently assembled in that the consecutive tube blanks on each side are welded together by means of weld seams 16,16 etc.

An alternative embodiment for a press cage section in accordance with the invention is shown in FIG. 3. Here the bridge elements 20 include integral extensions 22 for the bolts, and the bridge elements are welded together along weld seams 24,24 etc.

The number of bridge elements in each section will primarily depend upon the final dimensions of the screw press and the working pressures for which the press is designed.

FIG. 4 is showing a longitudinal cross-sectional view, partly schematic, through an assembled press cage in accordance with the invention and which altogether comprises three press cage sections. The separate sections are designated with numerais I, II and III, respectively. As it appears the inside diameter of each consecutive press cage section is constant, but is stepwise reduced from the inlet end to the outlet end, simultaneously as the external diameter of the bridges of all sections, however, is kept uniform and constant. Thereby is obtained a correspondingly stepwise increasing strength and stiffness of the cage from the inlet end (right end) towards the outlet end of the press. a

In the spacing between each adjacent two cage sections are positioned internally conical annular compression rings 30 and 32 which serve as diameter reducing transfer elements extending between each two press cage sections. Each of these rings 30 and 32 are preferably made in two substantially semicircular parts or if desired, in a suitable number of parts which in assembled state form an annulus. The compression rings, which constitute the primary compression means of the press, will further to radially directed pressure forces also receive axially directed forces, which are transferred through the cage sections to the bridge section at the outlet end which thus must be designed in order to be able to sustain this axial force.

In the shown embodiment the semi-circular compression ring parts do not register with each-other to complete the annulus, in that it will be noted from the drawing that the radial end faces of the ring parts are biased against the the opposing sides of the respective side bracket 7 located on each side of the cage, as shown at the number 40 in FIG. 4. Thereby is prevented that the compression ring or ring parts are rotated due to the rotational movement of the press screw and the material in the press cage when the press is in operation.

As it appears from FIG. 4 the upper part of each press cage section can be lifted up independently (after removing the bolts 5) of the other sections since the annular transfer elements are not rigidly connected, i.e. bolts or the like, to any of the sections and will in fact simply remain in position when the upper part of said section is removed. This is obtained by providing at the outside of the annular ring or ring parts a continuous circumferential seat 34 having an axial face 36 and a radial face 38 which faces are biased against the inside and end side, respectively, of the outermost bridge element on the adjacent cage section in direction against the outlet of the press. Hereby is obtained a rugged and simple design requiring very few parts, and being self-locking when the parts are assembled.

In the drawings is shown a press screw design for a so-called single screw press, but it will be understood that the invention with analogous advantages will be adaptable in connection with so-called double or twin screw presses.

What is claimed is:

1. In a screw press a press cage comprising a plurality of plate or disc-shaped cage elements assembled into a number of horizontally and/or vertically divided sections assembled in pairs, and mounted in a cage frame, each section comprising a cast or welded unit, the press cage having a progressively reduced inside diameter from the inlet to the outlet end, characterized therein, that the sections in the press cage have constant or uniform inside diameter, said inside diameter of consequtive section pairs gradually decreasing from the inlet to the outlet end of the cage, the pairs of press cage sections mounted in said frame with a spacing therebetween, said spacings provided with separate compression rings each of which has a conical inside face matching the adjoining inside faces of adjacent press cage sections, each of said compression rings comprising complementary ring parts supported by the respective adjacent press cage sections, said compression rings being provided with an external configuration presenting a peripherical seat at the one endside of the ring facing towards the outlet, said seat providing an axial face and a radial face, adapted to rest against the inside and endside edges, respectively, of the adjacent press cage bridge element, the other endside of said ring adapted to rest against the inside of the other adjacent press cage section, and a side bracket means supported by the cage extending inwardly between two meeting end faces on two parts of said compression i'i'ng and thereby providing a biasing means preventing theco'mpression ring from being rotated during the rotation of the press screw,

2. Press cage as recited in claim 1, wherein said compression ring comprises two substantially semi-circular complementary ring parts. 

1. In a screw press a press cage comprising a plurality of plate or disc-shaped cage elements assembled into a number of horizontally and/or vertically divided sections assembled in pairs, and mounted in a cage frame, each section comprising a cast or welded unit, the press cage having a progressively reduced inside diameter from the inlet to the outlet end, characterized therein, that the sections in the press cage have constant or uniform inside diameter, said inside diameter of consequtive section pairs gradually decreasing from the inlet to the outlet end of the cage, the pairs of press cage sections mounted in said frame with a spacing therebetween, said spacings provided with separate compression rings each of which has a conical inside face matching the adjoining inside faces of adjacent press cage sections, each of said compression rings comprising complementary ring parts supported by the respective adjacent press cage sections, said compression rings being provided with an external configuration presenting a peripherical seat at the one endside of the ring facing towards the outlet, said seat providing an axial face and a radial face, adapted to rest against the inside and endside edges, respectively, of the adjacent press cage bridge element, the other endside of said ring adapted to rest against the inside of the other adjacent press cage section, and a side bracket means supported by the cage extending inwardly between two meeting end faces on two parts of said compression ring and thereby providing a biasing means preventing the compression ring from being rotated during the rotation of the press screw.
 2. Press cage as recited in claim 1, wherein said compression ring comprises two substantially semi-circular complementary ring parts. 